Connectors that extend through pressure walls, wherein there is a different pressure on opposite sides of the wall, may require contacts that are tightly sealed to passage walls of the contact insulator. One way to provide a seal, is to form each contact with an enlargement that is of larger outside diameter than the inside diameter of a corresponding location along the insulator passage. The interference fit is intended to provide a fluid-tight seal. However, the seal at a contact enlargement may not be reliable, and it is desirable to provide a plurality of such seals as by providing a plurality of enlargements spaced along the length of the contact, which engage corresponding locations along the passage. However, it is found that even with a plurality of such seals, that fluid may leak through the passage. High reliability is required for connectors having a plurality of contacts, to prevent fluid leakage through any of the contacts.
When a pair of connectors are mated, the rear end of a first connector may be received within the front end of the second connector. It is usually desirable to provide a device that reliably holds the connectors together until they are intended to be unmated. In many applications, it is desirable that the retention device be of simple and low cost construction, and be very easily releasable, as by merely depressing a member.